1. Field of the Invention
The invention pertains to nose pads of spectacles or eyeglasses.
2. Brief Description of the Prior Art
A manufacturer of eyeglass frames, in order to compete effectively, must be able to provide eyeglasses at the lowest possible cost. As will be appreciated by those familiar with the distribution of consumer products, considerable cost savings can be realized if the number of different models in a given product line can be reduced.
Eyeglass frames vary in style to present a pleasing, aesthetic appearance, and thus a variety of different eyeglass models are provided for this reason. However, a manufacturer of eyeglass frames must also account for the distribution or range in size and proportions of the facial and anatomical features of the eyeglass market to which he is appealing. Because there is considerable variety in facial structure among the inhabitants of even the smaller localities and regions, a manufacturer of eyeglass frames must supply eyeglasses of different fitting sizes based, for example, upon the distance between the patient's eyes. Many eyeglass frames in use today have a simple, nonadjustable nose pad. For example, eyeglasses having molded eyeglass frames surrounding the lenses have rigid nose pads integrally molded therewith, and thus eyeglass frames for a particular eye spacing are relied upon to provide adequate support for a variety of individuals having different size and proportioned noses and more particularly, nose bridges, on which the eyeglasses rest.
The nose pads of a pair of eyeglasses are relied upon to maintain the desired alignment between the optical lenses and the patient's eyes. Although this alignment is not particularly crucial for plano lenses such as sunglasses, safety glasses or the like, this arrangement is particularly important for multifocal lenses. Apart from considerations of comfort during periods of extended wearing, eyeglasses should not vary widely in their wearing position relative to the wearer's eyes. Shifts in the position of eyeglass lenses will require a wearer to refocus or readjust his head when viewing an object at a fixed location. However, wearers of eyeglasses will readily appreciate that perspiration, humid or moist environments, and facial oil frequently cause the nose pads of an eyeglass frame to slip, thus bringing the eyeglasses lenses out of their desired position.
Turning now to issues of wearing comfort, many wearers have little fatty tissue at the bridge of their nose, and thus have a relatively low tolerance to the amount of pressure applied to the bridge of the nose by the eyeglass pads. Accordingly, it is desirable to reduce the pressure on the wearer's nose as much as is possible, and the best technique for achieving this goal is to increase the contact area between the nose pad and the wearer's nose to the greatest extent.
However, as has been outlined above, this goal is difficult to achieve if the eyeglass frames are not adjustable in their nose pad configurations, and where a single nose pad design must accommodate different wearers having a variety of nose configurations. U.S. Pat. No. 4,142,784 sought to relieve these problems by providing snap-in nose pieces of resilient material, such as a soft resilient plastic or the like. Several problems are, however, realized with this type of nose pad construction. For example, the nose pads must typically be quite bulky in appearance, and are thus objectionable for aesthetic reasons. Further, resilient plastic material, especially when exposed to the ultraviolet content of sunlight undergoes an aging process which reduces the material's resilience. Also, the properties of plastics materials vary significantly with temperature changes, especially colder temperatures, and the effects are more pronounced for plastics components of greater thicknesses.
U.S. Pat. No. 3,584,939, which provides a soft resilient arch overfitting the central bridge portion of an eyeglass frame, suffers from these same drawbacks, and accordingly a need remains for improved resilient nose support.